The care and feeding of animals in laboratory and commercial purposes and the like is a large endeavor carried on throughout the world. Often animals must be raised in very clean environments, and in very large numbers. It is necessary to keep to an absolute minimum the cost for raising each animal, due to the large numbers involved. It is also necessary to assure that the animals remain healthy in their cages.
A primary necessity in animal maintenance is providing water in sufficient amounts or on demand. It is genreally true that the easiest way to provide fresh water is in open watering systems such as troughs having flowing water therein. However, open systems are most easily contaminated by polluting materials. In the special case of birds maintained in a caged environment, the birds tend to fan their wings instinctively, for exercise, body cooling purposes, and the like. This habitual behavior creates air currents that blow pollutants such as droppings, feathers, trash, and foot into open watering systems. Contamination of the water causes disease in the animals, and the open watering system spreads the disease to nearby animals.
On the other hand, closed watering systems are far more resistant to contamination. Such systems generally comprise a water bottle affixed to each animal cage by a tension spring or the like, and a dispensing spout extending into the cage for the animal. However, water held in a bottle at ambient temperature tends to foster the growth of microorganisms within a short time, and it is necessary to frequently clean the water bottles and replace the water therein. These factors lead to a labor intensive endeavor that is costly both in outlays for individual water bottles and for the labor in maintaining the bottles.
Moreover, it is common wisdom that birds cannot be trained to drink from a closed watering system, in which it is necessary to act on a dispensing valve or element to release water. Thus most caged birds are provided with open water systems, such as fountains with open water surfaces, and the problems of water contamination and pollution continue unabated.
It is obvious that cost is a critical factor in maintaining animals in cages. Manufacturing cost of feeding and watering devices must be kept to a minimum. In addition, any improvement which decreases the cost of each bottle, or which decreases the time required to clean and fill each bottle would result in substantial savings.
Also, it is generally true that high sanitation standards must be maintained in most animal facilities. A drawback of prior art systems is that the spherical ball used to dispose the water is capable of rotating, and is indeed driven to rotate by the pecking action of the bird seeking water, if a bird can be trained for this task. The rotating ball delivers a drop of water to the animal, and returns minute bubbles of air to the feed tube to replace the water thus dispensed. The rotating effect unfortunately transfers saliva and food particles into the feed tube, where rising bubbles often carry the contaminating material upwardly to the tank supply. This action significantly degrades the quality of the water in the tank, and promotes the growth of algae and bacteria. It can also adversely affect the health of the animal.
Also, most water bottles known in the prior art for animal purposes employ a generally narrow opening and a narrow threaded cap which compressively seals the delivery tube to the bottle opening. Although this approach forms a generally sufficient seal, it also creates a difficult problem in attempting to clean the bottle to prevent undue accumulations of algae and bacteria in the bottles.
A further problem with prior art devices is that the means for metering the water flow to the animal are subject to wide fluctuations. The spherical ball may become lodged upwardly from the lower end of the tube, and prevent water flow to the animal. If an animal (especially lab animals) does not have water for even a short period of time, the animal's health may be adversely affected. Likewise, air bubbles may become trapped in the bent feed tube of prior art devices, and prevent water flow, with the same dire results.